kube-ps1 zsh prompt helper (#6507)

plugins/kube-ps1/README.md

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+Kubernetes prompt for zsh
+=========================
+
+A Kubernetes (k8s) zsh prompt that displays the current cluster cluster
+and the namespace.
+
+Inspired by several tools used to simplify usage of kubectl
+
+NOTE: If you are not using zsh, check out [kube-ps1](https://github.com/jonmosco/kube-ps1) designed for bash
+as well as zsh.
+
+## Requirements
+
+The default prompt assumes you have the kubectl command line utility installed.  It
+can be obtained here:
+
+[Install and Set up kubectl](https://kubernetes.io/docs/tasks/tools/install-kubectl/)
+
+If using this with OpenShift, the oc tool needs installed.  It can be obtained from here:
+
+[OC Client Tools](https://www.openshift.org/download.html)
+
+## Helper utilities
+
+There are several great tools that make using kubectl very enjoyable.
+
+[kubectx and kubenx](https://github.com/ahmetb/kubectx) are great for
+fast switching between clusters and namespaces.
+
+## Prompt Structure
+
+The prompt layout is:
+
+```
+(<logo>|<cluster>:<namespace>)
+```
+
+Supported platforms:
+* k8s - Kubernetes
+* ocp - OpenShift
+
+## Install
+
+1. Clone this repository
+2. Source the kube-ps1.zsh in your ~./.zshrc
+
+ZSH:
+```
+source path/kube-ps1.sh
+PROMPT='$(kube_ps1) '
+```
+
+## Colors
+
+The colors are of my opinion. Blue was used as the prefix to match the Kubernetes
+color as closely as possible. Red was chosen as the cluster name to stand out, and cyan
+for the namespace.  These can of course be changed.
+
+## Customization
+
+The default settings can be overridden in ~/.zshrc
+
+| Variable | Default | Meaning |
+| :------- | :-----: | ------- |
+| `KUBE_PS1_DEFAULT` | `true` | Default settings for the prompt |
+| `KUBE_PS1_PREFIX` | `(` | Prompt opening character  |
+| `KUBE_PS1_DEFAULT_LABEL` | `⎈ ` | Default prompt symbol |
+| `KUBE_PS1_SEPERATOR` | `\|` | Separator between symbol and cluster name |
+| `KUBE_PS1_PLATFORM` | `kubectl` | Cluster type and binary to use |
+| `KUBE_PS1_DIVIDER` | `:` | Separator between cluster and namespace |
+| `KUBE_PS1_SUFFIX` | `)` | Prompt closing character |
+| `KUBE_PS1_DEFAULT_LABEL_IMG` | `false` | Use Kubernetes img as the label: ☸️  |
+
+## Contributors
+
+Jared Yanovich

plugins/kube-ps1/kube-ps1.zsh

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+#!/bin/zsh
+
+# Kubernetes prompt helper for bash/zsh
+# Displays current context and namespace
+
+# Copyright 2017 Jon Mosco
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Debug
+[[ -n $DEBUG ]] && set -x
+
+setopt PROMPT_SUBST
+add-zsh-hook precmd _kube_ps1_load
+zmodload zsh/stat
+
+# Default values for the prompt
+# Override these values in ~/.zshrc or ~/.bashrc
+KUBE_PS1_DEFAULT="${KUBE_PS1_DEFAULT:=true}"
+KUBE_PS1_PREFIX="("
+KUBE_PS1_DEFAULT_LABEL="${KUBE_PS1_DEFAULT_LABEL:="⎈ "}"
+KUBE_PS1_DEFAULT_LABEL_IMG="${KUBE_PS1_DEFAULT_LABEL_IMG:=false}"
+KUBE_PS1_SEPERATOR="|"
+KUBE_PS1_PLATFORM="${KUBE_PS1_PLATFORM:="kubectl"}"
+KUBE_PS1_DIVIDER=":"
+KUBE_PS1_SUFFIX=")"
+KUBE_PS1_UNAME=$(uname)
+KUBE_PS1_LAST_TIME=0
+
+kube_ps1_label () {
+
+  [[ "${KUBE_PS1_DEFAULT_LABEL_IMG}" == false ]] && return
+
+  if [[ "${KUBE_PS1_DEFAULT_LABEL_IMG}" == true ]]; then
+    local KUBE_LABEL="☸️ "
+  fi
+
+  KUBE_PS1_DEFAULT_LABEL="${KUBE_LABEL}"
+
+}
+
+_kube_ps1_split() {
+  type setopt >/dev/null 2>&1 && setopt SH_WORD_SPLIT
+  local IFS=$1
+  echo $2
+}
+
+_kube_ps1_file_newer_than() {
+
+  local mtime
+  local file=$1
+  local check_time=$2
+  mtime=$(stat +mtime "${file}")
+
+  [ "${mtime}" -gt "${check_time}" ]
+
+}
+
+_kube_ps1_load() {
+  # kubectl will read the environment variable $KUBECONFIG
+  # otherwise set it to ~/.kube/config
+  KUBECONFIG="${KUBECONFIG:=$HOME/.kube/config}"
+
+  for conf in $(_kube_ps1_split : "${KUBECONFIG}"); do
+    # TODO: check existence of $conf
+    if _kube_ps1_file_newer_than "${conf}" "${KUBE_PS1_LAST_TIME}"; then
+      _kube_ps1_get_context_ns
+      return
+    fi
+  done
+}
+
+_kube_ps1_get_context_ns() {
+
+  # Set the command time
+  KUBE_PS1_LAST_TIME=$(date +%s)
+
+  if [[ "${KUBE_PS1_DEFAULT}" == true ]]; then
+    local KUBE_BINARY="${KUBE_PS1_PLATFORM}"
+  elif [[ "${KUBE_PS1_DEFAULT}" == false ]] && [[ "${KUBE_PS1_PLATFORM}" == "kubectl" ]];then
+    local KUBE_BINARY="kubectl"
+  elif [[ "${KUBE_PS1_PLATFORM}" == "oc" ]]; then
+    local KUBE_BINARY="oc"
+  fi
+
+  KUBE_PS1_CONTEXT="$(${KUBE_BINARY} config current-context)"
+  KUBE_PS1_NAMESPACE="$(${KUBE_BINARY} config view --minify --output 'jsonpath={..namespace}')"
+  # Set namespace to default if it is not defined
+  KUBE_PS1_NAMESPACE="${KUBE_PS1_NAMESPACE:-default}"
+
+}
+
+# source our symbol
+kube_ps1_label
+
+# Build our prompt
+kube_ps1 () {
+  local reset_color="%f"
+  local blue="%F{blue}"
+  local red="%F{red}"
+  local cyan="%F{cyan}"
+
+  KUBE_PS1="${reset_color}$KUBE_PS1_PREFIX"
+  KUBE_PS1+="${blue}$KUBE_PS1_DEFAULT_LABEL"
+  KUBE_PS1+="${reset_color}$KUBE_PS1_SEPERATOR"
+  KUBE_PS1+="${red}$KUBE_PS1_CONTEXT${reset_color}"
+  KUBE_PS1+="$KUBE_PS1_DIVIDER"
+  KUBE_PS1+="${cyan}$KUBE_PS1_NAMESPACE${reset_color}"
+  KUBE_PS1+="$KUBE_PS1_SUFFIX"
+
+  echo "${KUBE_PS1}"
+
+}